The present invention relates to a brake pivot, more particularly to a pivot for a cantilever brake of a mountain bicycle.
Referring to FIGS. 1(A)-1(D), a conventional pivot for a cantilever brake of a mountain bicycle is usually integrally forged from a circular metal rod, as shown in FIG. 1(A), to form a terraced pipe body successively having a large end portion 1, a flange portion 2 the diameter of which is far larger than said large end portion, a middle portion 3 and a small end portion 4, as shown in FIG. 1(B). A portion 21 of said flange portion 2 is commonly then cut down to form a lobe 22 protruding from the position between said large end portion 1 and said middle portion 3, as shown in FIG. 1(C), and an eye 23 is opened in said lobe 22, as shown in FIG. 1(D).
Said pivot is usually affixed in a fork of a bicycle at the end of said large end portion 1, rotatably supporting a cantilever on said small end portion while being resisted by a spring disposed around said mid portion. One end of said spring is attached at said eye 23 and the other end thereof is extended to engage with said cantilever. In addition, one end of said cantilever is usually connected with a brake wire and the other end of the same supports a brake shoe, so that said cantilever can be restorably rotated, depressing said brake shoe to make contact with a rim installed in the fork to brake the bicycle.
The conventional brake pivot has the following drawbacks:
The first being that, the process for forging the flange portion with the diameter which is far larger than said large end portion will generate internal stress and cracks within the pivot material, causing the transition section between said lobe 22 and said terraced pipe body to become brittle and fragile and therefore prone to tearing.
The second being that, the above-mentioned forging process is too complicated, and therefore too expensive to manufacture.
The third being that, cutting down the portion 21 from said flange portion 2 causes a waste of material.